[PEM12-P33] Observations of night time Sporadic-E layer by HF Doppler sounder network:
association with Medium-Scale Traveling Ionospheric Disturbance (MSTID)
Keywords:Sporadic-E (Es), MSTIDs
In this paper, we show an Es event on August 22, 2014 (00:00 to 02:00 JST). This Es event was analyzed in detail by Ejiri et al. (2019) who used a Lidar system to detect Es above Tokyo. The HFD system also detected the same Es feature near the Tokyo area. We made use of Es reflection data from the HFD receivers in Sugito, Saitama (36.0°N, 139.7°E), Fujisawa, Kanagawa (35.3°N, 139.5°E) and Sugadaira, Nagano (36.4°N, 138.3°E). By using this triangle observation, we succeeded in deriving the horizontal speed and direction of the motion of Es. In addition, we estimated the phase velocity of MSTIDs seen in the maps of Total Electron Content (TEC) from GPS receivers of GEONET. The Es layer propagated with a horizontal speed of 68.9 m/s in the azimuthal direction of - 113.0° from the geographic pole (approximately SWW). The phase speed of the simultaneously observed MSTIDs was estimated to be 68.1 m/s and the propagation direction was -110.1°. This striking correspondence of the dynamical characteristics of Es and MSTIDs implies that the E-F coupling is actually working in the generation process of summer night time MSTIDs and MSTIDs are moving in tandem with Es.